Synthesis and characterization of polyimides based on new fluorinated 3,3?-diaminobiphenyls

Abstract

Two new fluorinated diamine monomers, 3,3′‐diamino‐5,5′‐bis(trifluoromethyl)biphenyl and 3,3′‐diamino‐6,6′‐bis(trifluoromethoxy)biphenyl, as well as a known nonfluorinated analog, 3,3′‐diaminobiphenyl, were synthesized. Reaction of these diamines with rigid, highly rod‐like dianhydrides produced poly(amic acid)s and polyimides, which were spin coated and thermally treated to produce polyimide films for evaluation in electronics applications. It was hoped that these polyimide films would exhibit an ideal combination of low thermal expansion, reduced water absorption, and low dielectric constant but with improved elongation due to the “crankshaft” nature of the 3,3′‐biphenyl unit. Unlike polyimide films from analogous 4,4′‐diaminobiphenyls, however, the 3,3′‐diaminobiphenyl‐based polyimides did not yield low in‐plane thermal expansion coefficient in spin‐coated films. In some cases high elongation was achieved, but with high thermal expansion. These new diamines may nevertheless find utility in polyimides and polyaramides for membrane, fiber, and other applications. Additionally, they may be useful in modifying the properties of polymer backbones via copolymerization. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2441–2451, 1997

Development of Photosensitive Polyimide with Low Dielectric Constant.

“…Recently, PIs with a lower dielectric property and a higher dimensional stability are also required to develop high speed multilayer printed wiring boards (PWBs) and minimize the stresses between the films and the substrates [2]. Furthermore, a direct photo-patterning ability is necessary for PIs to reduce the number of processing steps in microelectronics fabrication by eliminating the need for photoresists.…”

“…Dielectric constants of all PIs were around 2.5 at 1 MHz with 54-62 ppm of CTEs. The € was found to be well correlated with calculated value which estimated by the Clausius-Mosotti equation (2 DHP is well known as a photosensitive compounds and is converted to corresponding pyridine derivative after UV exposure [8], and has been utilized for PSPI precursors [7]. Fig.…”

Preparation and properties of polyimide nanocomposites with negative thermal expansion nanoparticle filler

“…The rigid groups within the polymer backbone result in low in-plane CTE, but often cause reduced flexibility and processability compared to the original polymers, leading to failure under mechanical stress [7]. In addition, the design and synthesis of new monomers and PIs are expensive and tedious.…”

Synthesis and Properties of Novel Polyimides Containing Fluorinated Alkoxy Side Groups

“…[3] In most of cases, the introduction of fluorinated groups was carried out by chemical modification of aromatic diamines. [4,5] Some of the widely used approaches are based on the incorporation of a trifluoromethyl group directly attached to an aromatic group [6] or on the incorporation of a hexafluoroisopropylidene group in meta or para position of phenyl [7] or phenoxyphenyl groups. [8,9] Fluoroalkyl modified building blocks can for example be synthesised by condensation of bisphenol A or bisphenol AF with 2-chloro-5-nitrobenzotrifluoride followed by reduction.…”